The apparatus of the present invention relates to stump grinders, and more particularly to devices which are adapted to be mounted to bushhogs and which may be used to grind tree stumps situated in the ground.
In the modern practice of removing trees, it is possible to cut a tree trunk at or near ground level. The stump remaining in the ground is difficult to remove or destroy. Various devices have been employed to remove or destroy such tree stumps. Commonly these devices employ some means of cutting or grinding away the tree stump. One commonly employed device is a circular auger. Such devices are time consuming and difficult to operate and cannot readily be employed in the removal of large diameter tree stumps.
Some types of prior art stump grinders employ rotating circular wheels having grinding teeth located thereon. Typically these devices are employed with either manual or mechanical means to sweep the grinding teeth over the surface of the stump, thereby removing successive portions of the stump until an acceptable amount of the stump has been removed. An example of this type of stump grinder is found in U.S. Pat. No. 4,783,914 issued to Bowling on Nov. 15, 1988 for "Stump Remover." Bowling discloses a portable apparatus having a small internal combustion engine to provide rotational motion to a cutting assembly with four radially extending carbide teeth. The teeth are angled relative to the driving assembly. In use the device is manually swept across the surface of the stump so as to gradually grind away portions of the stump.
It is desirable to have a stump grinder that is capable of grinding away even large stumps in a single operation as opposed to the repetitive grinding operations that are common in the prior art. In a related art large circular disks arrayed with cutting teeth have been employed to cut trees and bushes. Typical examples of this type of apparatus are found in U.S. Pat. No. 4,998,573 issued to York on Mar. 12, 1991 for "Tree Cutting Apparatus" and U.S. Pat. No. 4,960,157 issued to Sheets on Oct. 2, 1990 for "Bush and Tree Cutter." Both York and Sheets disclose an apparatus which comprises a large circular disk having cutting teeth attached to the periphery thereof and means for simultaneously rotating the disk horizontally near ground level and moving the disk linearly so as to sever a tree trunk or bush. This type of apparatus is not, however, adapted to the removal of tree stumps since the teeth of the cutters are typically mounted radially outward from the periphery of the circular cutting disk.
In a related art large circular disks are mounted with a plurality of cutting teeth on the underside thereof so as to grind up tree stumps that have been removed from the ground. An example of such a device is found in U.S. Pat. No. 5,054,703 issued to Morey on Oct. 8, 1991 for "Stump Chipper Knife Assembly." Morey discloses a stump disintegrator in which cutting knives are arrayed in pockets formed in a rotating chipper disk such that the knives protrude from the face of the disk.
A common type of bush and tree cutting apparatus is known as a "bushhog." A description of such an apparatus is found in U.S. Pat. No. 5,237,803 issued to Domingue, Jr. on Aug. 24, 1993 for "Centrifugal Combination Sprayer/Cutter Apparatus", which is incorporated herein by reference. Domingue, Jr. discloses a combination sprayer/cutter apparatus which is adapted to be attached to a bushhog. The prior art does not disclose, however, a stump grinder apparatus adapted for attachment to a bushhog.